Actually the only thing he is selling is the benefits of drinking distilled water. I recommend you listen to the show before taking down the link. As I said I have my own battle with my 9 yo son's UC but I do recognise that during my research I often come across treatments that may help other diseases. This is one such treatment that is so simple, safe and cheap.
The basis behind this treatment, and I quote from Dr. Charles Mayo of the Mayo Clinic:
"Water hardness (inorganic minerals in solution) is the underlying cause of many, if not all, of the diseases resulting from poisons in the intestinal tract. These (hard minerals) pass from the intestinal walls and get into the lymphatic system, which delivers all of its products to the blood, which in turn, distributes to all parts of the body. This is the cause of much human disease."
Couchtater, you hit the nail on the head by saying it is very clean water. The theory behind it is because it is totally "pure" it acts by attracting all the toxins, hard minerals etc out of your body, joints etc. Perhaps Dr Mayo was right and mineral deposits may be a possible cause of degenerative diseases like fibromyalgia, arthritis, etc.